Fuel burning apparatus



P. s. ARNOLD FUEL BURNING APPARATUS Dec. 15, 1942.

Filed Sept. 9, 1959 'INVENTOR. flan/77$. 19: 4am M kw;

I ATTORNEY.

Patented Dec. 15, 1942 UNITED STATES PATENT OFFICE 2,305,129" FUEL BURNING APPARATUS,

Philip s; Arnold, Flint, Mich. Application-September 9, 1939, SerialNo; 294,171

1 Claim. (c1. 158-1) This inventionrelates to fuel burning-apparatus and the manner of supplying fuel incom bustion to a furnace or-combustion chamberand is a continuation in part ofmy application, Serial No. 720,826, filed April 16, 1934, now U. S. Patent'No. 2,175,866, issued October 10, 1939, and certain features of construction herein described and'clai-med are also shown in my co-pending application, SerialNo. 294,170, filed September 9, 1939.

' It is also a principal object of the invention to'provide apparatus for burning fuel whichinvolvesza combustion of a fuel in a chamber exteriorlyof--a furnace anddischarging the gases while at approximately combustion temperature to the'upp'er part of the heating chamber of a furnace to flow downwardly therein and-discharging the same therefromat a point-below the point of introduction.

These and other features and objects of'the invention arehereinafter-morefully described and a convenient form ofapparatus employing my improved methodof burning fuel is shown'in the -accompanying drawing in. which- Fig. 1 is-an elevation showingf my improved burner as applied'to a domestic heating furnace.

Fig; 2 is an enlargedvertical-section of the burner proper and-the associated control devices.

In Figs. l and-2 is shown a preferred form of the construction'and arrangement of the burner and" the means for supplying air and oil" under pressure thereto, the burner" being housed in the casing indicated -at- I- and to this casing is connectedaconduit 2 opening to the smoke flue 3 ofthe furnace indicated generally at '4. valve 5 is provided in-the smoke flue 3 which, when in the open position as shown in Fig. 2, directs the gases of combustion into the flue and into the radiator ring 6 or chamber of the furnace through which the'gases of combustion-usually pass when used in the ordinary way in the burning'offuel and in my arrangement, these gases pass downward throughthe radiator, fliepot, grate, ashpit, and thence out through an auxiliary flue 'I which is here shown as discharging into the smoke flue 3 adjacent the stack (not shown) in the wall 8. The heating of these usual channels for heated gases in a hot air furnace heats the air in the exterior shell of the furnace and-this heated air passes through the preferably-metal,- and'the'exterior thereof mayhave-an insulatin'gcovering Ia particularly about that portion thereof immediately surrounding the combustion chamber II to prevent material loss of heat'to atmosphere; I

The combustion chamber II is preferably formed of a refractory material and the bottom section thereof, indicated at I2, is greater in diameter thanthe body, I3. The. bottom; wall of thechamber is provided with a series of apertures I4 for inflow of air and the side walls of the bottom portion I2 are provided with the tangential apertures ,I5. Thebody of the chamber above the bottom wall has apertures I6, prefere ably tangential, opening therethrough. There are also a series of air inlet holes I'Iat the open upper end I8 of.- they combustion chamber II.

Thisend I8 closestheinteriorof the casing I to the conduit 2 so that air in the casing must pass into the combustion chamber I I-to complete combustion. The flue 2,'valve 5, and the walls of the smoke flue 3 to the point of entrance into the combustion chamberand channel 6 of the furnace are lined with a fire resistant material indicated at I9. To the,- bottom wall of the combustion chamber II and adjacent the nozzle 22 is connected a fuel pipe 20- having a valve 2I for control thereof to, provide a pilot light. Liquid or other form. of fuelin atomized condition is discharged through the nozzle 22 into the bottom section I2; of the combustion chamber as shown inFig. 3 from which it will be'observed that the atomizing nozzle by dischar ing thefuel stream tangentially into the chamber causes the supplied fuel to pass circumferentially thereabout inzorder that burned and/or unburned gases will partially or Wholly envelop the fuel jet. This condition is enhanced by extending the wall of the chamberat the nozzle aperture inwardly of the circumference to provide a *shieldfor the nozzletand preventing contact of free air with the jet.

Ignition of thefuel takes place in thebottom section I2 ofth combustion chamber II and the inflowing fuel body is raised in temperature to above the combustion temperature. To continue the combustion; theiopeningsalli are provided in the bodyin order todischarge air into the gases passing upwardly toward'the smoke flue'3 of the furnace. Air passing through these apertures I4,

I5, I6 and [Tin the'form of combustion chamber shown in Fig. 2 is providedby-a fan 35 which is positionedabove a dividing wall 36 inthe casing Iand takes its supply through an aperture 31 opening to the lower chamber 38 of the member I. The chamber 38 is openatits bottom to atmosphere through a conduit"39having a valve for varying the area of the opening, the control of which is hereinafter described. The fan 35 is driven by a motor 4| supported on a base 42 suspended from the dividing wall 36 by the studs 43.

For supplying air under pressure to the nozzle, I provide a two-cylinder compressor supported from the base 42 on which the motor is mounted and this apparatus consists of a casing providing a chamber 44 containing oil for lubrication purposes and the compressor consists of the two outwardly disposed cylinders 45 and 46 and companion pistons operated alternately by any approved means as an eccentric 41 on the motor shaft.

The said shaft has a bearing in a central column 48 in the chamber 44 and the column has an aperture 49 opening into the chamber below the oil surface and leading upwards to the bearing for the motor shaft. The pistons have the usual spring valve 50 in the outer end which opens on the instroke of the piston and closes on the outgoing stroke and the head of the cylinders is formed with an aperture 51 covered by a recessed plate 52. recess of this plate to the interior of the chamber 44. Thus the air is taken from the interior 38 of the casing I in which the compressor is mounted through the casing of the motor 41 and through apertures Me in the base 42 and is discharged into the chamber 44 and thus the oil in the said chamber is under pressure and is caused to lubricate the bearing for the motor and compressor. This oil under pressure may,

by a conduit, (not shown) lead to any part of the apparatus which requires to be oiled.

The chamber 44 acts as a storage tank for air under pressure and the air line 25 has its intake end in this chamber above the oil surface and upturned as shown to prevent any material amount of oil entering the same. The air line 25 opens to the oil line 27 to the rear of the nozzle 22. The compressor may be of any type providing for substantiallyconstant air pressure.

The control of the burner in operation is accomplished by the following described mechamsm:

Connected into the fuel supply pipe 21 is a control valve 55 and this valve has a stem 56 connected to a lever 51 hinged at one end to a diaphragm casing 58 and the opposite end of the lever 51 is connected by means of a rod 59 with the valve 40 controlling the air inlet to the casing through which the fan 35 is supplied. The lever 51 has a spring 60 tending to close the fuel valve 55 and also to restrict the air opening through the turning of the air valve 40. The lever also has a bearing 51a opposite the pivotal connection with the oil valve stem 56 engaging the flexible diaphragm Bl forming one wall of the casing 58. The chamber of the casing 58-is connected to the air line 25 by a pipe 58a through which air under pressure is supplied to automatically open the valve and permit flow of oil. Thus it will be observed that the oil valve 55 and the valve or shutter 40 may both be operated or adjusted in unison and the proper proportion of the air and oil are admitted to the combustion chamber II for accomplishing complete combustion. The construction shown in Fig. 2 is an arrangement adapted for use with oil or gas as a fuel. With a powdered fuel some change in construction of the valve would be required but the relationship of the parts would be substantially the same.

An aperture 53 is provided from the The compressor preferably has a constant output greater than is required by the atomizing nozzle or nozzles and to control the operation of the burner, I provide a thermostat, indicated generally at 62, which may be located at any convenient point of the building or space to be heated. The thermostat consists of a bimetal helix 63 for operating a needle valve 54 normally closing the opening to a conduit 65 connected with the air line 25 here shown as being connected to the line 25 through the conduit 58a for the diaphragm chamber. Due to an excess temperature in the heated space the thermostat opens the conduit 65 permitting escape of air, thereby reducing the pressure in the diaphragm chamber 58 permitting the lever to act under tension of the spring 60 to partially close the valve 55. Under the-opposite condition, that is, a reduction in temperature of the heated space, the helix operates to close the needle valve 64 which tends to build up the pressure in the diaphragm chamber thereby opening the fuel valve 55 to a greater extent and also opening the valve or shutter at 46 to increase the air flow to the fan 35 and thus increasing the heat output of the burner.

There is an additional safety control shown generally at 66. This safety control is shown in Fig, 4 of my U. S. Patent No. 2,175,866, of October 10, 1939, and is herein shown in face view in Fig. 1 by means of which a disc 69 having a notch 10 in its periphery is rotated to bring the notch 10 opposite the pin H permitting the lever 12 to be moved by a spring 11 to open the valve 14 releasing the air pressure and closing the fuel Valve. Flow of raw oil into the combustion chamber is thus prevented.

Whenthe temperature of the helix shown in said Patent No. 2,175,866 is not increased by combustion gases passing through the radiator ring from the combustion chamber II the disc rests in such a position that a pin 'Il mounted on the end of a pivoted lever 12 is held in the notch by tension of the spring 11. The lower end of the lever 12 is connected by a link 13 with a needle valve '14 having a stem riding in a guide 15. The valve may seat in the end of the tube 16 connected with the air supply pipe 58a and thence with the main air supply pipe 25. The toggle structure'consisting of the lever 12 and link I3, is so arranged that when the pin H rests in the notch in the disc 69, the needle valve 14 is open.

To start the burner,the lever 12 may be manually held in the position shown in Fig. 2 with the valve 14 closed. This causes a rise of pressure within the air supply pipe through operation of the motor and compressor which is understood to be in operation at the time and the consequent deflection of the diaphragm 6! to the position shown in Fig. 2 opens the fuel valve. After the fire has been burning a short time the helix in the furnace radiator ring 5, which has become heated, rotates the disc so that the lever upon release by the operator has the pin H resting upon the periphery of the disc thereby holding the needle valve 14 closed and the fuel valve 55 open permitting the burner to continue in operation.

It is to be seen from the foregoing that there are preferably two instrumentalities for controlling the oil burner, one consisting of the thermostat structure 62 for varying the rate of consumption of oil to correspond with the temperature changes in the room being heated, and the other consisting of the safety control 66 both of which operate through a release of air pressure in the air supply connected to the nozzle or nozzles. The room thermostat structure 62 and capacity of the port controlled by the needle valve 64 is such as to reduce the pressure but not to such extent as to quickly or fully close the fuel valve and its operation is therefore to control the amount of fuel consumed While the structure indicated generally at 66 is adapted to cause complete cessation of the fuel flow.

It will be observed that in the event of breakdown of the oil burner structure and necessity for continued use of the furnace through consumption of fuel within the furnace itself, the valve 5 in the smoke flue 3 is closed and a valve 71a in the flue I is closed. This permits the furnace to be operated in the usual way with the fire in the grate indicated by the dotted line 18 and the products of combustion will pass out through the usual smoke flue 3. Under this condition, the valve plate 5 prevents soot or dust from entering the oil burner chamber. When used with the oil burner the valve 5 is open and the valve 11a is also open so that the products of combustion pass through the radiator ring 6 downward through the furnace and out through the flue I,

With a rotating body of the gases and air entering only from the exterior of the gaseous body, the central portion does not in some cases receive suflicient air for combustion or at least for complete combustion by the time the gases pass from the chamber and this, of course, varies with the diameter of the body of the rotating gases. By the arrangement shown, the gaseous body is provided with air in the interior as Well as the exterior thereof.

By the construction of the combustion chamber hereinbefore described, a complete burner outfit may be installed in conjunction with an ordinary wood or coal burning heating furnace without removal of any of the usual furnace parts leaving it all in normal state. The installation may be made at very little cost, it being only necessary to provide the flue I open to the ash pit of the furnace and to the exhaust flue 3 of the furnace to which the discharge flue 2 of the combustion chamber is connected and also to provide a threaded opening in th radiator ring or correspondingly similar structure of the furnace combustion chamber for introduction of the safety trip 66,

The burner may thus be completely set up in all its relationship of parts even including the trip 66 at the factory and practically adjusted prior to installation and thus upon installation and connection of the thermostat 62 and air supply -pipe therefor and the oil supply pipe the installation is completed and ready for opera tion.

While I have shown the combustion chamber in a housing I and discharging through the usual smoke flue into the furnace it is to be understood that the furnace may be of any usual construction having hot air conduits through which air heated by the gaseous products of combustion pass downwardly through the furnace. The invention therefore is not confined to the specific furnace structure shown. Whatever the furnace structure may be the gaseous products of combustion are passed from the combustion chamber l l at one side of the furnace into the usual smoke flue 3 of the furnace and by means of the valve 5 are directed into the top of the furnace and the burned gases pass from the bottom of the furnace through the flue 'l to the exhaust flue 3 between the valve 5 and the chimney 8 and it is with this arrangement of parts that the apparatus shown in Fig. 2 may be associated with a furnace without material change in the furnace parts.

From the foregoing description it is believed evident that the various objects of the invention are attained by the structures described, and that a comparatively simple and economic construction is secured.

Having thus described my invention, its utility and mode of operation, what I claim and desire to secure by Letters Patent of the United States 15:

Fuel burning apparatus comprising a main furnace, a smoke flue extending to one side of said furnace adjacent the top thereof, an auxiliary combustion chamber at one side of the furnace, an outlet conduit extending from the bottom of the furnace to the said smoke flue at a distance from the furnace, a flue extending from the upper end of the auxiliary chamber and discharging to the said smoke flue between the furnace and the point of connection of the said outlet conduit with the smoke flue, and a valve in the smoke flue between the respective points of connection of the flue of the auxiliary combustion chamber and of said outlet conduit therewith to closeosaid smoke flue when said auxiliary combustion chamher is used to heat the said main furnace.

PHILIP s. ARNOLD. 

